Summary:During a transatlantic flight from New York City to London, U.S. Air Marshal Bill Marks receives a series of cryptic text messages demanding that he instruct the airline to transfer $150 million into an off-shore account. Until he secures the money, a passenger on his flight will be killed every 20 minutes. Surrounded by only a couple of people he initially believes are trustworthy, the resourceful air marshal must use every nuance of his training to uncover the killer traveling on board the aircraft. What follows is a nail-biting cat-and-mouse game with the lives of hundreds of passengers hanging in the balance.